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Toward the Complete Prediction of the 1 H and 13 C NMR Spectra of Complex Organic Molecules by DFT Methods: Application to Natural Substances
Author(s) -
Bagno Alessandro,
Rastrelli Federico,
Saielli Giacomo
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200501583
Subject(s) - chemical shift , chemistry , spectral line , computational chemistry , nmr spectra database , molecule , polarizable continuum model , coupling constant , carbon 13 nmr , formalism (music) , solvent effects , solvent , stereochemistry , physics , organic chemistry , art , musical , visual arts , particle physics , astronomy
The NMR parameters ( 1 H and 13 C chemical shifts and coupling constants) for a series of naturally occurring molecules have been calculated mostly with DFT methods, and their spectra compared with available experimental ones. The comparison includes strychnine as a test case, as well as some examples of recently isolated natural products (corianlactone, daphnipaxinin, boletunone B) featuring unusual and/or crowded structures and, in the case of boletunone B, being the subject of a recent revision. Whenever experimental spectra were obtained in polar solvents, the calculation of NMR parameters was also carried out with the Integral Equation‐Formalism Polarizable Continuum Model (IEF‐PCM) continuum method. The computed results generally show a good agreement with experiment, as judged not only by statistical parameters but also by visual comparison of line spectra. The origin of the remaining discrepancies is attributed to the incomplete modeling of conformational and specific solvent effects.